1. Field of the Invention
The invention relates to an item with a surface area exhibiting an optical effect. Also within the scope of the invention is a process for manufacturing the item and the use thereof.
2. Background Invention
Proof against forgery in packaging is of great importance especially for the pharmaceutical industry. Basically, however, in other branches of industry there is a wish for forgery-proof packaging or products, in particular in the consumer industry, e.g., the packaging of foodstuffs, cosmetic items, clothes, software and music CDs or bonds. The item with the surface area exhibiting the optical effect may be packaging, packaging material, an aid to packaging or a product itself on which a surface area is provided with a security part, e.g., in the form of a label bearing an optical effect.
Forgery-proof packaging or packaging material may serve as guarantee of origin, enabling the customer to recognize that the purchased item was actually manufactured and packaged by the desired manufacturer. Forgery-proof packaging material may also be used as guarantee of first opening, e.g., in the form of a label, band or sealing strip, etc., which has, e.g., been affixed to the goods over a bottle closure or over a closure on a wide-necked glass, across a seam between a lid and a container or over the tear-off closure on a pouch. On opening the packaging in question the label, band or sealing strip is broken, demonstrating that the package has already been opened. It is also possible to place objects in an outer packaging bearing characteristic, unmistakable features that cannot be copied, showing that the packaging of the contents has been performed by a particular supplier.
Known forgery-proof packaging and products are provided with holograms on their surface or they exhibit color coding or invisible features. Methods that have proved themselves in practice include, e.g., holograms. Examples are hologram labels or foil lids with integral holograms. Manufacturing holograms, however, involves enormous expenditure.
The object of the invention is therefore to provide at least a part of the surface of items, such as, packaging, packaging materials, packaging aids or products themselves, with an optical effect that can be produced in a cost favorable manner, but cannot be forged in a simple manner.
That objective is achieved by way of the invention in that the surface area exhibiting the optical effect exhibits at least two images separated a distance from each other by means of a transparent layer of material, and such that the distance between the images and the distance between two neighbouring elements forming the images are adjusted with respect to each other, and such that on altering the viewing angle the perceived overall image formed by the overlapping of the images is altered.
The invention makes use of a phenomenon known as the moirxc3xa9 effect. Moirxc3xa9 patterns are two dimensional images that result from the interference of two overlapping patterns. By displacing two immediately adjacent patterns, the moirxc3xa9 interference pattern also changes, leading to the known, changing light-dark image effects.
The present invention makes use of the changing moirxc3xa9 interference that occurs without mechanical displacement of the pattern. As a result of the mutual distance between the images, a spatial arrangement results, which on changing the angle of viewing leads to chang-ing moirxc3xa9 interference effects. By using reflecting materials it is possible, in the region of the angle of reflection, to observe a reflected image of one of the images instead of moirxc3xa9 interference patterns, while moirxc3xa9 interference occurs outside the range of the angle of reflection. The essential core of the invention lies therefore in the preparation of a three dimensional moirxc3xa9 pattern.
In order to create the effect according to the invention, the already known distances between neighbouring image elements in the moirxc3xa9 pattern have to be maintained. The said patterns may be made up of individual parallel lines or dots. In the simplest case of a line pattern the distance between neighbouring lines is always the same. In a simple arrangement two identical image patterns are arranged directly over each other and a distance from each other. It is possible, however, to displace regions of one image pattern with respect to the other image pattern e.g. by half the distance between neighbouring image elements, or to provide the first image with another pattern with the result that, on changing the angle of viewing, for example several changes from lightness to darkness and vice versa are observed. Of course images may also contain a combination of straight and curved lines or other image elements. As a result it is e.g. possible to incorporate trade names and the like signs with three dimensional moirxc3xa9 effects in the packaging material. In order to increase the protection against forgery further, one of the images may contain an additional structure to that of the pattern of lines. Another means of increasing protection against forgery and to conceal data is to design the image in such a manner that the additional information can be seen only after an additional filter has been superimposed on the image. Such filters are made up of a grid-type pattern, the dimensions of which are chosen to suit the dimensions of the line pattern.
The transparent layer of material that acts as a spacer between the images serves as a means of setting the desired minimum distance. This cannot be changed if the patterns are mounted immediately on the different sides or planes of the transparent material layer. If however the transparent layer lies on at least one of the images without being permanently attached there, i.e. at least one of the images is free of the layer of transparent material, then the distance from the pattern is variable and the three dimensional moirxc3xa9 effect is even more pronounced.
The layer of transparent material may be provided with an image on both sides. Another version is such that the layer of transparent material is made up of at least two partial layers and the images are deposited on the different partial layers. In a further version one of the images is deposited on an opaque foil e.g. an aluminium foil.
Instead of two images being deposited, one image may be the mirror image of the other. In this case one side of the layer of transparent material borders on the reflecting layer e.g. an aluminium foil with a highly reflective finish.
The images may be deposited in the form of coloured printed patterns. The printed image may be monochromatic or multi-coloured. As additional security one may employ colours that make the moirxc3xa9 pattern visible only under UV or IR light. Another possibility is for at least one image to be in the form of a surface structure with structural elements displaced with respect to their height e.g. as an embossed or etched pattern. Embossed or etched structures are suitable e.g. for depositing images on an aluminium foil. Embossed patterns may also be deposited on plastic or aluminium/plastic laminates using hot and/or cold embossing. Foils or laminates with an image pattern in the form of a surface structure are especially suitable for the production of tube laminates e.g. for manufacturing toothpaste tubes.
The images may also be created in the form of micro-perforations on an opaque foil, especially on an aluminium foil. The diameter or breadth of the perforations is thereby about 10 to 1000 xcexcm, preferably 50 to 200 xcexcm.
The images may also include basic matrix elements with individual image elements, the related image elements of different basic matrices being displaced with respect to each other in order to produce different local light-dark contrast or colours. The image preferably form patterns that produce defined light-dark contrast or colours as a result of various combinations of superposition. As these kind of images require extremely good matching of the super-imposed basic matrices to produce a good effect, this kind of image is required mainly in applications requiring a high degree of security against forgery.
The items according to the invention are manufactured using known methods. The image may be deposited e.g. by simultaneously printing on both sides of a transparent plastic film. The individual images may however also be printed on different films. The individual films, each bearing a printed image, are then joined by laminating them together to provide a packaging material. The proof against forgery is increased even further in that the laminating has to be performed on a machine with high precision control of the printing process.
At least one of the images may be deposited on a further layer of material which is free of the transparent layer of material. The optical effect is produced only when both layers of material are brought close to each other, the three dimensional moirxc3xa9 effect being additionally altered and reinforced. The two layers of material may e.g. be two foils or laminates that are joined together only at certain places, otherwise the other areas are able to adopt a variable distance to each other. Application possibilities are e.g. in pouch-type packaging made of two lamin-ates that are joined or sealed together only at the edges.
The item according to the invention may e.g. be any packaging material in the form of a packaging material or aid to packaging exhibiting a transparent layer of material upon which, additionally according to the invention, images have been deposited. The packaging material may be rigid, semi-rigid or flexible and may have a given shape or in particular be a foil-shaped material. Examples of shaped bodies are blown, deep-drawn and/or stretch drawn or deepened shapes such as bottles, wide-neck containers, beakers, dishes or bases of push-through packs or blister packs. Examples of foil-shaped materials are metal foils such as aluminium, steel, copper, silver or gold foils. Further examples of foil-shaped materials are papers such as silk paper having a weight per unit area of 20 to 30 g/m2 or highly whitened paper with a weight per unit area of 40 to 60 g/m2, cardboard, semi-cardboard or the like. Particularly important are films containing plastic e.g. plastics based on polyolefins, such as polyethylenes or polypropylenes, polyamides, polyvinylchloride, polyesters such as poly-alkylene-terephthalates and in particular polyethylene-terephthalate. The films containing plastic may be in the form of mono-films of plastic, laminates of two or more plastic films, laminates of metal and plastic films, laminates of papers and plastic films or laminates of papers and metal and plastic films. The individual plastic films may have a thickness e.g. of 12 to 200 xcexcm and the metal foils a thickness of 12 to 100 xcexcm. The individual layers of foil-shaped materials may be joined together by means of adhesives, laminating adhesives, bond-ing agents and/or extrusion coating, co-extrusion or laminating etc. Preferred plastic films are non-oriented or axially or biaxially oriented mono-films or laminates of two or more non-oriented or axially or biaxially oriented films of plastics based on polyolefins such as poly-ethylenes or polypropylenes, polyamides, polyvinylchloride, polyesters such as polyalkylene-terephthalates and in particular polyethylene-terephthalate.
The above mentioned packaging materials may form the items according to the invention in the form of packaging materials or aids to packaging. For example pouches, sachets, wraps, bags etc, may be manufactured out of the film-shaped packaging materials by stamping and sealing. By deep drawing and/or stretch drawing, films may be shaped into shaped packaging or shaped bodies such as bases of push-through packs or blister packs, or into wide necked containers, menu dishes, goblets, beakers etc. For example tubes (tube laminates) or lids for shaped packaging may be shaped out of the films in question. One may manufacture e.g. boxes such as collapsible boxes from cardboard type substrates. It is also possible to employ e.g. bottles blown out of plastics, or pre-formed packaging as a substrate and to apply the transparent material according to the invention to it. Closures, openings, seams, seams between a base part and the related lid etc. may be provided with a packaging material according to the invention in the form of a label, sealing strip, band, guarantee seal or outer seal. These last mentioned aids to packaging are as a rule film-shaped and are fixed to the container in question across an opening and fixed, e.g. adhesively bonded, welded, flanged or shrunk-fit onto the neighbouring part of the container. The packaging aid exhibits the trans-parent layer of material according to the invention and the images spaced apart by this. The structure according to the invention of the surface or area of surface on the item results in the specific intended optical effect on changing the angle of viewing. A forgery e.g. by photo-copying and using the photocopy as evidence of product origin or guarantee would be recog-nised immediately and easily, as changing the angle of viewing would not lead to the optical effect that is observed with the structure made according to the invention. In order that the aid to packaging e.g. sealing strip or band can be easily broken by the user, aids to tearing such as forms of weakening, notches or tear-off tabs may be provided. Also, component parts of packaging materials or aids to packaging may be employed in the form of easily torn or push-through plastic films, or plastic films containing fillers, or two poorly compatible plastic films.
Apart from the already mentioned use of the item according to the invention in the form of packaging or aid to packaging, another field of application is the forgery-proof manufacture of bonds, entry tickets and the like documents, whereby in addition to the forgery-proof design aspects it is possible to introduce special decorative effects.